This disclosure relates to rotors that have blades which are mounted in slots in a rotor disc. More particularly, the disclosure relates to the lay-up of layers for a blade wedge attachment.
Rotors, such as turbine rotors in gas turbine engines, typically include a disc that has axially extending slots around its periphery for mounting turbine blades. The slots have a “toothed” profile and each of the blades has a root with a corresponding profile to interlock with the toothed profile of the slots. In applications in which the blade is constructed from multiple layers forming a ceramic matrix composite, the root typically is provided by a simple dovetail geometry.
Typically, the rotor is joined to an airfoil of the blade through a relatively narrow neck and root joined at a fillet. One challenge in securing the blades is that during operation, stresses on the blade can be concentrated at a relatively narrow neck and fillet. Another challenge is that interlaminar stresses in the CMC can cause delamination between the layers.
One technique for mitigating stress is to secure metallic pads near the neck and fillet. Another technique for mitigating stress is to provide wedges that float with respect to the slot and the blade tooth.